Archaeologists examining the 1,600-year-old remains of a woman from Roman Spain have made a unique – if grisly – discovery: a calcified ovarian tumour containing four teeth and a piece of bone.

Known as a ‘teratoma’,  the spherical mass measured 4.3cm (1.7in) in diameter and was found in the right-hand part of the woman’s pelvis by researchers from the Autonomous University of Barcelona (UAB). Two teeth were loose inside the growth, with two more enclosed by a lump on its inner surface.

Taking their name from the Greek teras, or ‘monster’, and onkoma, or ‘swelling’, teratomas are  tumours which contain organic material such as hair, bone, teeth, and tissue. They rarely survive in the archaeological record, and where examples have calcified, as in this case, they can easily be mistaken for other pathologies such as kidney or bladder stones, or for rocks. The UAB team’s findings, published in the International Journal of Palaeopathology, represent the first-known ovarian teratoma found in an individual from Antiquity.

‘The calcification and preservation of the external walls of this tumour are exceptional,’ said the study’s co-author, Assumpcio Malgosa. ‘These types of remains usually only retain the internal structures, and the extremely fragile external ones disappear.’

Aged 30-40 when she died, the woman was one of 46 burials excavated by the UAB in 2010 at La Fogonussa, a 5th-century BC necropolis in modern Catalonia.  She had been laid to rest with pairs of tegulae (clay tiles) arranged over her like a gabled roof.

Researchers have not ruled out the possibility that the tumour may have caused the woman’s death, but as teratomas are usually benign and 60% of modern cases cause no symptoms at all,  she may have lived her whole life with no sign that anything was wrong.